President Barack Obama plans to nominate the Navy's cybersecurity chief to become the next director of the National Security Agency and the commander of the U.S. Cyber Command.

Vice Adm. Michael Rogers, currently the commander of U.S. Fleet Cyber Command, will be named to the post, said Defense Secretary Chuck Hagel on Thursday. If confirmed by the Senate, he will succeed Gen. Keith Alexander, who has held the NSA post since 2005....